Braun tube



K. SCHLESINGER Zl BRAUN TUBE Filed Aug. 4, 1932 Patented Apr. 21, 193e 2,038,061

UNITED STATES PATENT GFFICE BRAUN TUBE Kurt Schlesinger, Berlin, Germany Application August 4, 1932, Serial No. 627,441 In Germany August 10, 1931 2 Claims. (Cl. Z50-27.5)

When employing Braun tubes lilled with a gas fashion. Since the disturbing distortions occur of suitable pressure, operated with an anode voltin the direction of the oppositely situated adage of more than 1000 volts and working with jacent deflecting plates, it has proved to be conray currents of more than 10-4 amperes, more venient to arrange the leakage plates parallel 5 particularly for television purposes, distortions to the adjacent delecting plates. The invention 5 have been found to occur which, by reason of is set forth more precisely in conjunction with a their practically regular occurrence in adjacent few possible forms of embodiment. lines, must be laid down to oscillating charges In Fig. 2, 3 is a Braun tube having two pairs in the glass wall which form between the screen of dee'cting plates 4 and 5, the Wehnelt cylinand the deflecting elements. These distortions der 6, the cathode 1 located therein and the 10 assert themselves in part in the form of undusocket 8. 9 is the luminous screen on which the latory deections vertical to the movement of disturbing fringing action makes itself apparent. the beam (fringing). Distortions, however, have By the provision of the ring I0, and taking the also been ascertained in the direction of the same to earth, it is possible, as stated above, to

beam, making themselves apparent in the form prevent the disturbing effects. In Fig. 3 there 15 of small nodules on the luminous screen. An is illustrated the same arrangement having two example of fringelike distortion is illustrated in partly annular electrodes Il; the remaining parts Fig. l. In this there is shown the luminous are designated by the same reference characters screen of a Braun tube, on which screen the as in Fig. 2. The electrodes lll or Il may be arcathode ray traces the rectangular image proranged inside the glass tube. It has been found 2o duced by a television transmitter. Whereas at yet more suitable to situate them on the excertain points: l of the path of the ray no disterior of the glass wall. tortion takes place, the disturbing fringing ac- I claim: tion is found at other points. 1. A Braun tube comprising an envelope, a

These distortions, as already stated above, are gas lling Within said envelope, a cathode and 25 to be laid down to oscillating glass wall charges, an anode mounted in cooperative relation in said which are controlled in undesired fashion, probenvelope for producing a cathode beam in the ably byv electrode or external elds. According order of at least 10-1 amperes, two pairs of deto the invention in Braun tubes of the above lecting plates, a picture receiving screen and mentioned kind the ions forming these charges two electrodes, each consisting of a thin metallic 30 shall either immediately be leaked ol or recoating, said electrodes forming parts of an antained by suitable means. For the purpose of nulus and being mounted on the inner side of leaking-off it is convenient to employ a metallic the wall of said envelope between said deflecting coating which is applied to the inside of the glass plates and said screen for preventing the occurwall and is connected with an adapted potential, ring of fringelike distortions, said electrodes be- 35 for example, with earth, or for retaining puring adapted to be connected to a source of conposes a coating which is applied to the outer stant potential. wall and is also conduotively connected with 2. A Braun tube comprising an envelope, a gas earth or another constant potential. The dislling within said envelope, a cathode and an turbances made themselves apparent more paranode mounted in cooperative relation for pro- 40 ticularly in the case of high anode potentials, ducing a cathode beam in the order of at least 1000-4000 volts, and strong ray currents of the 10-4 amperes, two pairs of deilecting plates, a order of 10-4 amperes or more. picture receiving screen and two electrodes, each The form of the leaking or retaining coating consisting of a thin metallic coating, said elecis decided in part by the form of the glass wall, trodes forming parts of an annulus and being 45 and therefore preferably constitutes part of a mounted on the outer side of the wall of said cylinder. As experiments have shown, both an envelope in parallel to the plates of one of said annular portion of this kind as well as two oppopairs of deflecting plates between said deflecting sitely disposed sections of such a ring are found plates and said screen for preventing the occursuitable. When employing two of these sections, ring of fringelike distortions, said electrodes be- 50 it has been found particularly convenient to ing adapted to be connected to a source of conplace these opposite to each other in the direcstant potential. tion of the disturbing deections, and to con- KURT SCHLESINGER, neet the same with each other in conductive 

